Customer can't sign up to Pro Sites

Hi,

Here's what the customer is saying:
"It looks like your credit card application is not working. I have tried to use a couple different cards and it doesn't take it.
No error messages, after I submit the card it looks like it will process but brings me back to a blank credit card submission page."

Also I am not getting any notifications that a site has been created which normally happens even if the payment doesn't go through.

Although I do see them in the system as a user:
calden3

Thanks.

Kind regards,

Justin Peach